Experience with Microsoft Fabric MQTT Connector

1

Is there any experience around connecting Microsoft Fabric’s MQTT Connector to HiveMQ? I can connect, I see events flowing in but I get errors stating that there was a problem with deserialization:

    "Message": {
        "value": "First Occurred: 1/3/2026 11:01:07 AM UTC | Resource Name: es-embeddedeventhub | Message: Source 'EventHubInputAdapter' had 137 occurrences of kind 'InputDeserializerError.InvalidData' between processing times '2026-01-03T10:56:10.0742327Z' and '2026-01-03T11:01:07.8418533Z'. Json input stream should either be an array of objects or line separated objects. Found token type: Float\r\n",
        "type": "string"
    },

Thanks,

Thomas

2

Hi @TePe,

Thank you for your detailed description.

From the error message, it appears that your MQTT client is currently publishing raw float values, while the Microsoft Fabric MQTT connector expects JSON-formatted payloads. This mismatch causes the deserialization error on the Fabric side.

Could you please update your MQTT publisher to send JSON objects instead, for example:

{"value": 12.3}

After making this change, test the flow again and let me know if the issue is resolved or if you still see any errors. I will be happy to continue investigating if needed.

Best regards,
Dasha from HiveMQ Support Team